Snap action switch



Dec. 11, 1956 A. w. HAYDON SNAP ACTION SWITCH Filed June 18, 1953 R m MA:olllllrrillolllllll!llv ATTORAEYS United States Patent '0 SNAP ACTIONSWITCH Arthur W. Haydon, Cheshire, Conm, assignor to Haydon Switch,Incorporated, Waterbury, Conn., a corporation of Connecticut ApplicationJune 18, 1953, Serial No. 362,505

2 Claims. (Cl. 200-67) This invention relates to snap action switches,and more particularly to modifications of the snap action switchdisclosed in copending application Serial No. 363,107 filed June 22,i953.

In the aforementioned application there is fully disclosed and claimedwhat may be termed 'a'single pole double throw hermetically sealedswitch useful for the control of two interdependent electric circuits orfor the control of a single electric circuit. For certain applicationsitis desirable to provide a "switchto control two completely independentelectric circuits. "For other applications it is desirable toprovide 'aswitch capable of controlling three interdependent 'electrical circuits.The primary object of this invention "is therefore to provide snapaction switches, of the general type disclosed in the aforementionedcopending application, which are suitable for use in the control of -twoindependent electrical circuits or for use in the control of threeinterdependent electrical circuits.

The snap action switch of the aforementioned copending applicationcomprises a casing in which are mounted three terminal rods, twoadjacent one end thereof and the third adjacent the other end thereof.To the third terminal is secured one end of a spring blade, the otherend of which supports apair of contacts, one on either side, and extendsbetween the remaining two terminal rods. The spring blade is normallysupported so that one of the contacts on its free end engages a contacton one of the last mentioned terminal rods. When the switch is actuatedby means of an actuating member mounted in the wall of the casing thespring blade is moved with a snap action from its normal position withits free .end in contact withone of the terminal rods of the pair to aposition in which the other contact on its free end engages a contact onthe other terminal rod of the pair.

The present invention contemplates :modifications of the above snapaction switch in which the free end of the spring blade is mounted tomove back and forth upon actuation of the switch from contact with apair of terminal rods supported on one side thereof to a single terminalrod supported on the other side. The free end of the spring blade isprovided with a contact on its side adjacent the single terminal rodadapted to engage a contact mounted on said terminal rod. Upon the otherside of the free end of the blade is supported what may be termed aconnecting bar, each end of which is adapted to engage a contact mountedon one of the pair of terminal rods on that side of the blade when thefree end of the blade is moved toward said pair of terminal rods. In themodification useful in controlling two independent circuits, theconnecting bar is supported from the free end of the blade by dielectricmaterial electrically insulating it from the blade. In the modificationuseful for controlling three interdependent circuits, the contact bar issupported from the free end of the blade by conducting materialelectrically connecting it to the blade.

For a more detailed understanding of the invention and the advantagesthereof, reference may be made to the following .more specificdescription taken in connection with the accompanying drawingin which:

Fig. l is a perspective of a switch according to this invention;

Fig. 2 is a sectional view thereof taken along line 2-2 of Fig. 1;

Fig. 3 is aplan view of the switch, partly-in section and with a portionof the casing removed; and

Fig. 4 he sectional view taken along line 44 of Fig. 2 illustrating moreclearly the construction of the connecting 'bar support means.

The switches of this .application each comprise, as does that of "theaforementioned copending application Ser. No. 363,107, a cup-like casingmember 10 having anopen side surrounded by a flange 11 and adapted to beclosed for hermetic sealing by a casing closure 12 which is receivedwithin flange 11 and secured to the casing member 10 .by a fluid tightseal. A spring blade supporting terminal rod 13 supported in a glasssealing compound support 14 extends through closure member 12 having itsinner end flattened at 13 to support a spring blade 16 andapa'irofiblade supporting members I7 and 18 which varesecure'd theretoby rivets19. A pair of 'tubuIarSmembersZt) extend completely through theswitch casing and are sealed at opposite ends by fluid tight sealingmeans, .such as solder, to .the bottom of casing member IOand .toclosure vmemberlZ. An auxiliary support member 21 of cylindrical formfor aiding in the positioning and support .o'f'blade support member '18is mounted on a tubular member 22 which is supported in a glass sealingcompound support 23 in closure member 12. The interior of the switch 'isadapted to be evacuated through tube 22 and filled, if desirable, withinert gas and the tube thenpinched off and sealed.

The spring blade 16 includes a central compression member 16' normallyarched out of the plane of the blade and a pairof tension members 16" oneither side thereof. Blade support member 18 engages the convex side ofcompression member 16 while blade support member 17 having dependingblade-engaging portions 17' engages tension members 16" of the blade,the latter being crimped, as indicated, to shorten their lengths andimprove their resiliency under longitudinal tension. The outer end 17 ofblade support member 17 supports a button 3% of material such as nylonengaged by a switch actuating pin 31 mounted in a flexible supportmember 32. Flexible support member 32 is preferably made of a siliconerubber compound and is supported in an opening in one wall ofcasingmember 10. The flexible support 32 for the actuating pin 31 issecured thereto by a fluid tight seal and further is secured by a fluidtight seal to a flange 33 bounding the opening through the side wall ofcasing 10.

As thus far described, switches of this invention are identical to theswitch disclosed in copending application Ser. No. 363,107 and referenceto that application is suggested for a more complete description of theelements of this switch as described so far, as well as for a completedescription of the operating characteristics of those elements.

In the switch of the copending application, the spring blade 16 wasprovided at its outer end with a pair of silver contacts, one on eitherside thereof, these contacts being adapted to alternately engage a pairof contacts similar to contacts 40 and 41 of the present switch whichare mounted on terminal rods 42 and 43, respectively, supported in thecasing closure member 12 by two glass sealing compound seals 44 and 45.In the switches of this invention, however, a single silver contact 50is secured as by welding to the upper face of the outer end of springblade 16 and is adapted, when the switch is in normal condition, toengage with a positive pressure contact 40 to complete a circuitincluding terminal rods 13 and 42 and spring blade 16. On the other sideof the free end of spring blade 16, instead of a second silver contactcomparable to contact 50, there is mounted a shorting or connecting bar60. When the switch is actuated and the contact between contacts 40 and50 is broken, connecting bar 60 is adapted to electrically connectcontact 41 on terminal rod 43 to a contact 62 secured to a terminal rod63 mounted in closure member 12 by a glass sealing compound support 64.Connecting bar 60 is preferably made of silver and is supported from theend of the spring blade by support member 70 partially surrounding theend of the spring blade, as illustrated most clearly in Fig. 4, andhaving a post 71 of square or non-circular cross section dependingtherefrom and extending through an opening of similar cross sectionalshape in connecting bar 60, the bottom end of the post 71 being flaredout to prevent removal of the connecting bar therefrom.

Supporting post 71 is located substantially centrally of the end of theblade and is of smaller cross section than the opening 72 in theconnecting bar whereby the connecting bar is very loosely supported bythe post and may rock to a limited extent. Support member 70 isadditionally provided with a ridge 73 extending transversely of theblade between connecting bar 60 and the end of the blade, ridge section73 acting as a fulcrum substantially to limit rocking movement of theconnecting bar to a direction longitudinally of the blade. The mountingof connecting bar 60 by support member 70 for rocking movementlongitudinally of the blade is' essential in order that tight contact beeffected between connecting bar 60 and contacts 41 and 62 when theswitch is actuated.

In a switch suitable for controlling two independent circuits, supportmember 70 and its components are made of any suitable dielectricmaterial capable of withstanding the heat generated at the free end ofthe spring blade during operation of the switch. Hence the connectingbar is fully insulated from the spring blade. One of the circuitscontrolled will be that previously indicated including terminal bars 13and 42 and the switch blade. The other circuit that may be controlled isentirely independent and includes terminal members 43 and 63 andconnecting bar 60.

in a switch for controlling three interdependent circuits, the supportmember 70 may be made of an electrically conductive material such assilver. In this case, of course, the connecting bar 60 is electricallyconnected to spring blade 16 and the three circuits that may becontrolled each include terminal rod 13 and spring blade 16 and one ofterminal rods 42, 43 or 63.

In a switch of this category, the support member need not be as large involume as is shown, and in fact it is desirable that it not be so,because of the weight that would be involved. In this instance, the post71 and the connecting bar rocking ridge 73 may be secured directly tothe end of the spring blade 16 as by welding.

Certain changes and modifications in the switches of this invention mayreadily occur to those skilled in the art, but it should be understoodthat the scope of the invention should not be limited by reason of thisfact but rather only to the extent set forth in the appended claims.

I claim:

1. A snap action switch comprising a spring blade supported at one end,the other end being free to move when the switch is actuated, a switchcontact mounted opposite one side of the free end of the blade, a pairof switch contacts mounted opposite the other side of the free end ofthe blade, a support member of a dielectric material mounted on andsubstantially surrounding the free end of the blade, said support memberhaving a depending post extending in the direction of said pair ofswitch contacts, a connecting bar loosely mounted on said post againstrotation relative thereto, said connecting bar being adapted to engageand electrically connect said pair of switch contacts when the switch isactuated and the free end of the blade is moved toward said pair ofswitch contacts, pivot means associated with said support adjacent saidpost to provide for pivotal movement of the connecting bar about alateral axis when it is moved into contact with said pair of switchcontacts, and a contact mounted on the free end of the blade inelectrical contact therewith and on the opposite side thereof from saidpost, said lastmentioned contact being adapted to engage the switchcontact mounted opposite said one side of the free end of the blade whenthe switch is actuated and the free end of the blade is moved towardsaid switch contact.

2. A snap action switch according to claim 1 in which the support memberof dielectric material includes a ridge extending transversely of thefree end of the blade, said ridge being laterally aligned with said postand maintaining said connecting bar spaced from the free end of theblade, said ridge also providing a fulcrum for pivotal movement of saidconnecting bar in a direction longitudinally of said blade.

References Cited in the file of this patent UNITED STATES PATENTS2,202,440 Beach May 28, 1940 2,238,621 Bletz Apr. 15, 1941 2,446,961Sherlock Aug. 10, 1948 2,649,520 Hartz Aug. 18, 1953 2,662,941 FisherDec. 15, 1953

